Mobile communication systems have been developed in order to provide a communication while securing a mobility of users. With remarkable technological development, the current mobile communication systems can provide a high speed data communication service as well as a voice communication service.
Recently, the 3rd Generation Partnership Project (3GPP) is arranging standardizations for the Long Term Evolution (LTE), as one of the next generation mobile communication systems. The LTE is a technology for realizing a high speed packet based communication having a transmission speed of a maximum of about 100 Mbps, which is higher than the currently provided data rate, with targeting at commercialization thereof around the year of 2010, and the standardization job for the LTE has been nearly completed.
Meanwhile, in pace with the completion of the LTE standardization job, discussions about the LTE-Advanced (LTE-A), in which various new technologies relating to the LTE communication system have been grafted, has now started in earnest. One of such new technologies includes a contention based access technology.
The contention based access technology has been proposed in order to solve the problems of the typical uplink transmission according to the prior arts. The typical uplink transmission is performed through dedicated transmission resources allocated by a Base Station or Node B, and an allocation of transmission resources requires a preliminary process of requesting a Node B to allocate the transmission resources by a User Equipment (UE), which may increase the transmission delay.
In order to solve such problems described above, the contention based access technology allows a Node B to use a part of transmission resources as resources for the contention based access. Since the transmission resources having been notified as the resources for the contention based access can be freely used by UEs which will transmit data, signal collision may occur when multiple UEs transmit signals through the same transmission resource. Such a signal collision may remarkably reduce the possibility that the corresponding signals can be successfully decoded in a Node B.
Therefore, there has been a request for a scheme capable of minimizing occurrence of signal collision in a contention based access.